Tiffen's 67mm Soft Contrast 2 Glass Filter has a light absorbing element in the filter which, without exposure compensation, will reduce contrast by also darkening highlights. Use this latter filter when lighter shadows are not desired. In both cases, the mild flare produced from bright highlights is sometimes used as a lighting effect.
Works with surrounding ambient light
Captures details lost in shadows
Lowers contrast evenly throughout image
No flare or halation
Lets you "see" more